In the 3 holes on well-cooked (therefore very hard) granite tile, it melted. Although the manufacturer's usage instructions regarding the number of rotations, etc., were strictly followed. It certainly is not for a lifetime, but its price does not justify its short lifespan.

It is supposed to be for granite, but in the first two or three holes, one broke and the other melted, so I don't know, I wasn't satisfied.

Very good. It did the job with very hard granite tiles. Like all, it broke at the 6-7 hole but it paid for itself